There have been proposed and employed various types of electrophotographic printers wherein a toner image is transferred to a fan-fold sheet such as a continuous-form recording sheet. In order to avoid wasting paper, the fan-fold sheet is first fed out of the printer to allow the last printed page to be detached from the continuous form, then the fan-fold sheet is retracted into the printed so that the next image will be printed on the subsequent blank sheet. In order to accomplish this, a pair of tractor mechanisms c and d, as shown in FIG. 6 have been employed. The mechanism c is located along the fed path, upstream from the transfer station b, while the mechanism d is located down-stream of the transfer station b.
However the use of two tractor mechanisms requires precise synchronization, which is difficult and expensive to achieve, and increases the size of the printer unit.
In order to overcome the above defects, one proposal has been to use only one tractor mechanism, with the tractor belt having one end located upstream of the transfer station and the other end downstream of the transfer station. The tractor belt thus contacts the recording sheet along the feed path and at both sides of the transfer station. However, since the tractor belt is disposed below the photoconductive drum, the pins on the belt used to mesh with the holes in the recording sheet will contact the photoconductive drum thus damaging the photoconductive coating of the drum.
Another possible modification is to employ a single tractor mechanism having a trapezoidal circulation path to guide the fan-fold sheet until the sheet enters into the transfer area and immediately after the sheet exits the transfer area, with this modification, damage to the surface of the photoconductive drum can be prevented, but other problems such as the jamming of the sheet around the transfer area and the peeling-off of a label from a substrate when a label sheet is used, may occur.